Stress relieving apparatus and method

ABSTRACT

An apparatus for stress relieving an aluminum-containing material by immersion in a molten metal bath. The bath is selected from the group consisting of lead, lead and tin, and lead and bismuth. The aluminum-containing material is fed through the bath at such rapid linear velocities that stripping means must be provided to prevent a pumping action between the material and the bath. In a preferred form when feeding aluminum wire through the bath, this stripping is effected by passing the wire through one or more orifices whose diameter is only slightly larger than the diameter of the wire. A method of producing lead particles is disclosed by slightly increasing the orifice diameter of the stripping means when employing a lead bath.

United States Patent [72] Inventors Ogle R. SlngletonJr. [56] References Cited g g a' z J Ch t n M C t UNITED STATES PATENTS ney er. r., es er e oun y; r

2,728,567 12/1955 Farnworth et al. 263/3 3 Highland springs 2,8 I 8,075 12/1957 Dunlevy et al 263/3 x [21] Appl. No. 858,284 Primary Examiner.lohn J. Camby [22] Filed Sept. 16, 1969 Attorney-Glenn, Palmer, Lyne, Gibbs & Thompson [45] Patented Nov. 16, I971 [73] Assignee Reynolds Metals Company Richmond, v ABSTRACT: An apparatus for stress relieving an aluminumcontaining material by immersion in a molten metal bath. The bath is selected from the group consisting of lead, lead and tin, and lead and bismuth. The aluminum-containing material is fed through the bath at such rapid linear velocities that stripping means must be provided to prevent a pumping action [54] ig fii fi b fiz g g AND METHOD between the material and the bath. In a preferred form when 8 8 feeding aluminum wire through the bath, this stripping is cf- [52] US. Cl 263/3, fected by passing the wire through one or more orifices whose 266/3 diameter is only slightly larger than the diameter of the wire. A [51] Int. Cl F27b 9/28 method of producing lead particles is disclosed by slightly in- [50] Field of Search 263/3; creasing the orifice diameter of the stripping means when em- 266/3. 4 A; l48/l8 ploying a lead bath.

I04 .t 1 7?) Rewind PATENTEDunv 16 I97! 3,620. 5 1 6 sum 2 or 4 INVENTORS Ogle R. Single/0n, Jr BY Sidney B. Kes/er, Jr

W/l/iclm E. Warren ATTORNEYS PATENTEDunv 16 I971 3.620.516

sum 3 OF 4 1 7'0 Collector I N VENTORS Ogle R Single/on, Jr

BY Sidney B. Kes/er, Jn

/' //a 5'. Warren ATTORNEYS PATENTEDuuv 1s IHYI SHEET H []F 4 INVENTORS @445 ATTORNEYS "wifiiiiiilllllllll S W .M M

STRESS RELIEVING APPARATUS AND METHOD This invention relates to an apparatus for stress relieving aluminum-containing material and, more particularly, to stress relieving aluminum-containing material by immersion in a lead-containing, molten metal bath. As an unexpected byproduct, a method of producing lead particles is disclosed when employing a molten lead bath.

I-leretofore it has been customary to stress relieve and anneal aluminum-containing material such as aluminum wire and aluminum strip in furnaces and resistance-type annealers. This-apparatus has been not only expensive to construct but also time consuming to operate. Furthermore, when aluminum wire, for example, has been treated in resistance-type annealers the spools over which the wire has been fed has been subjected to arcing resulting in short circuits and has in general proven to be deleterious. The aluminum has a tendency to gall and when small amounts of oxide or dirt are picked up, arcing begins under the heavy current requirements such as 35-50 amperes. The problems have not been solved despite meticulous handling techniques including ex tensive cleaning and brushing procedures.

In accordance with the present invention the foregoing problems are effectively bypassed in a stress relieving treatment which utilizes the inherently high heat transfer coeffi cients of liquid metals to heat solid aluminum. Thus heat transfer coefficients of about 6,000 BTUs per hour per square foot per degree Fahrenheit difference with a range of about 2,000 to 10,000 are possible in the molten metal treatments of the present invention. A typical heat transfer coefficient for an air furnace is about 8 BTUs per hour per square foot per degree Fahrenheit difference.

In the practice of the present invention new problems arise, the principal one of which is concerned with the viscous (fluid) drag. The material being treated such as wire acts as a mechanical pump. The wire can entrain molten metal from the bath for a considerable distance above the bath. In order to deal effectively with this problem, orifice plates preferably made of graphitic carbon are used to act as strippers to hold back the liquid metal bath. The orifice plates are centrally bored to a nondrawing dimension with respect to the aluminum wire which passes therethrough. The pumping action also results in a drag force resisting the passage of the wire. Since the wire gets weaker as it becomes hotter, the drag forces have a tendency to reduce the wire diameter. The results of the treatment in accordance with the present invention show that a wide range of operating conditions are possible in order to obtain desired stress relieved mechanical properties in the treated metal, particularly in variation in the ultimate strength, yield strength and percent elongation. Because of the extremely short treating times involved, for example, less than about I second, polygonization rather than an annealed condition is obtained.

The molten metal bath possesses the characteristics of being nonwetting with respect to aluminum-containing material. For this purpose, lead is particularly well suited. Composite baths of lead and certain other metals are also possible. Thus combinations of lead and tin and lead and bismuth are satisfactory.

The inherent advantages and improvements of the present invention will become more readily apparent upon considering the following detailed description of the invention and by reference to the drawings in which:

FIG. 1 is a front elevational view showing one general arrangement of the apparatus for stress relieving aluminum wire in accordance with the present invention;

FIG. 2 is a fragmentary front elevational view of a portion of the wire feeding apparatus, drawn to an enlarged scale;

FIG. 3 is an elevational view, in vertical cross section, illustrating one stripper means of the present invention;

FIG. 4 is a plan view, taken in horizontal cross section, along line 4-4 ofFIG. 3;

FIG. 5 is a side elevational view of a modified stripper means;

FIG. 6 is a fragmentary front elevational view similar to FIG. 2 showing another position of the wire-feeding apparatus;

FIG. 7 is a fragmentary elevational view, taken in vertical cross section, showing a portion of the wire feeding and stripping means and illustrating a method of making lead particles; and,

FIG. 8 is a front elevational view similar to FIG. I but showing a different post treatment operation.

While the various features of this invention are hereinafter illustrated and described with respect to specific embodiments of treating aluminum wire, it is to be understood that the various features of this invention can be utilized singly or in a variety of combinations with respect to aluminum strip material.

Therefore, this invention is not to be limited merely to the embodiments illustrated in the drawings because the drawings are utilized herein merely to illustrate one of a wide variety of uses of this invention.

Referring now to FIG. 1 of the drawings, there is illustrated a wire feeding apparatus indicated generally at 10 which includes a spool of wire 12. In a typical application, an aluminum wire 14 may be EC H-l9, cold drawn to either 17 or 24 B&S gauge from annealed 0.375 diameter rod. The aluminum wire is fed through suitable eyelets l6 and past a wiper means 18 which may conveniently consist of felt wipers spring urged together by spring means similar to a clothespin. The felt wipers are preferably impregnated with a suitable lubricant such as peanut oil or W motor oil. The wire is fed over suitable guide rollers 20 mounted on stand 22 and then to a large guide roller mounted in front of a large hood 25 which removes fumes emanating from the molten metal in tank 27.

Referring now to FIG. 2, there is illustrated a holder means indicated generally at 26 the lower portion of which may be inserted into the tank 27 after the wire 14 has been threaded therethrough. Thus the holding means 26 is shown to comprise a pair of vertical support members 28 which are provided with a plurality of mounting holes 30 to receive bolts 32. A top cross plate 34 is secured thereby. Extending laterally outwardly from the vertical support members 28 are a pair of lateral extensions such as shown at 36, one of which holds a large guide roller 24 secured by bolt 37. The holding means 26 is further provided with a bottom cross plate member 38 with a suitable locking member 40. Plate members 42 and 44 are attached to the bottom to a respective one of the vertical support members 28 and are disposed in abutting relatio.. in FIG. 2. However, in order to provide means to vary the length of travel that the aluminum-containing material is immersed in the molten metal bath, the pair of vertical support members may be separated as shown in FIG. 6. This may be effected either by providing a larger top cross plate member 34a and a larger bottom cross plate member 38a or by attaching the vertical support members 28 directly to the sides of the tank 27 in difierent spaced locations.

The plate members 42 and 44 are each provided with a series of guide rollers 46 in order to guide the wire 14 as it is immersed in the molten metal 58 within tank 27 and to redirect it outwardly therefrom. it is desirable to control the temperature of the molten metal 27 within very close limits in order to obtain predictable properties from the aluminumcontaining material which passes therethrough. To facilitate temperature control, thermocouples indicated generally at 48 are provided as required throughout the tank and especially near the entrance and exit of the wire from the tank. Thus the thermocouple wires 50 may be positioned substantially as shown in FIG. 2, in order to obtain this temperature data and to be able to control the temperature by conventional means within reasonably narrow limits. Resistance heaters 51 may be used to supply heat to the molten metal 58, as required. Also one or more recirculating pumps 53 are used to recirculate the molten metal 58 within tank 27 so as to preserve substantial uniformity of temperature for the molten metal within the tank. Other control features include the use of an inert atmosphere such as nitrogen, or the use of a reducing atmosphere, such as carbon monoxide. Carbon powder may be used to float on the molten metal surface If desired, in addition to the wiping action afforded the aluminum wire 14 by the felt wiper element 18 in FIG. I, a holder 52 mounted on plate member 42 may be provided with a wiper or stripper element therein to 'wipe the wire immediately prior to its entry into the molten metal 58. The nature of the wiper or stripper element therein will be described hereinafter in connection with a similar stripper element 64 disposed in the exit stripper means. The purpose of the inlet wiper is to prevent lead oxide from adhering to the aluminum wire.

Another holder 54 is provided at the locus of outlet or exit of the wire from the molten metal bath 58. In this instance. it is essential to provide the wiping or stripping afforded by the exit stripper means indicated generally at 60. The exit stripper means is contained within an insulating member 62 in order to ensure that the stripper means is maintained at a temperature at least as great as the melt temperature of the molten bath material. For example, when a lead bath is employed. the minimum temperature is about 620 F. After the wire has begun to be fed through the stripper means 60, the combined effects of friction and contact with the molten bath material is sufi'lcient to maintain the stripper means above the melting temperature of the molten metal. As seen in FIG. 3, first stripper element 64 may be held in place either by thumb screws 56 or by a setscrew inserted into a bore 66 shown in FIG. 4. The first stripper element 64 is provided with a Iongitudinally extending orifice 68 and a pair of channels 70 by which the molten metal may be returned to the molten metal bath. As an adjunct thereto or in lieu thereof. the insulating member 62 may be provided with a pair of channels at 72 for the same purpose. A second stripper element is shown at 76 having a longitudinal bore or orifice 78 and is shown to be threaded into the end of the insulating member 62.

FIG. illustrates an alternate embodiment for the first stripper element 64 wherein the alternate stripper element 90 having a pair of channels 78 corresponding to the pair of channels in stripper element 64 is further provided with a plurality of cross bores or holes 92 whereby a plurality of longitudinally spaced orifices are provided within the single stripper element 90,

As the wire 14 emerges from the exit stripper means 60 it passes over a series of guide rollers 86 which are mounted on mounting plate 82 which is attached to one of the lateral extension members 36 by means of bolts 84.

Referring again to FIG. I, the wire continues under the influence of a conventional rewind mechanism, not shown. over a guide roller 94 preparatory to being immersed in a quench means indicated generally at 96. For example, a water quench may be provided by disposing water in tank 98. A pair of arms 100 support guide roller 102 as well as guide roller 94 in order to feed the wire into and out of the water quench. Thereafter, the wire is fed over suitable guide rollers 104 to a rewind station in conventional manner.

Alternatively, the wire 14 may be subjected merely to air or to a spray cool as indicated at 106 and then passed over guide rollers 108 into and out of a plastic bath 110 within tank 112 in order to provide a plastic coating to the aluminum wire. Thereafter. the wire is fed to a rewind or spooling operation.

In operation. the aluminum-containing material. such as aluminum wire 14 is threaded through eyelets I6, spring loaded felt wiper 18. over rollers 20, large guide roller 24 on holder means 26. through the wiper within holder 52, over guide rollers 46 on each of plate members 42 and 44, then through the exit stripper means 60, over the series of guide rollers 86, and thence either to the water quench means 96 or into the plastic bath 110 as shown in FIGS. I and 4, respectively. Finally the wire passes to the rewind apparatus which provides the driving force for the aluminum wire. The bath 58 in tank 27 is brought up to a desired temperature by means of resistance heaters 51. The recirculating pumps 53 maintain the bath in constant circulation and the temperature of the bath is sensed by suitable thermocouple means 48 at various selected points throughout the bath. The temperature is cycled within close limits at a preselected temperature by conventional means, not shown. The outlet stripper means 60 may be heated directly by suitable means to ensure that its temperature is at least as high as the melting temperature of the molten metal bath 58.

The stripper means contained within holder 52 is not so critical as the exit stripper means and is provided merely to ensure that no scum on the surface of the lead bath contaminates the wire. On the exit stripper means 60, however, it is important that the bore 68 of the first stripper element 64 is only slightly larger than the diameter of the wire in order to prevent a pumping action between the wire and the molten metal bath. This pumping actionhas a geyserlike effect if not suitably controlled. The first stripper element 64 does substantially all the work and the second stripper element 76 merely completes the stripping job. The first stripper element 64 is provided with the channels 70 in order to return the molten metal which is stripped from the wire to be returned into the bath. The wire moves at very high speeds in excess of 500 feet per minute and preferably is maintained in the molten metal bath for a period less than about 1 second.

As a completely unexpected result, it was found that when the bores 68 and 78 of stripper elements 64 and 76 respectively were too large or became worn so as to be nonsymmetrical, that it was possible to produce lead fibers as indicated at in FIG. 7 from a bath of molten lead while continuously stress relieving aluminum wire. Thus it was a relatively simple matter to vector the lead fiber to a collector, such as a pot.

There is a problem with friction not only in the stripper means 60 but also in the rollers such as 24. 46 and 86. Therefore. it is preferred that these guide rollers be made of a temperature withstanding material, for example, graphitic carbon.

In order to measure the performance and to measure the properties obtained from the aluminum-containing material as treated in accordance with this invention, the initial properties of the wire are measured prior to treatment by the molten metal bath and the wire is tagged by suitable means during the rewind operation for later identification and testing.

Reference to table 1 illustrates representative tests performed on 24 8&8 gauge EC wire in the H-l9 condition. Prior to immersion in a molten lead bath the mechanical properties were measured for the wire which was found to have an ultimate tensile strength of 28.8 k.s.i. (thousands of pounds per square inch), a yield strength of 27.3 k.s.i. (thousands of pounds per square inch), and an elongation of 0.87 in 10 inches of length. The wire diameter was measured to be 0.0l99 inch. After treating the wire in the apparatus shown in FIG. 1 and tagging samples identified in table I as 1 through 12, the wire was again measured and found to have an ultimate tensile strength of 27.6 k.s.i., a yield strength 25.4 k.s.i., an elongation of l.3 percent in l0 inches, and a diameter measured to be 0.0200 inch. Intermediate these two measurements, the wire was subjected to a molten lead bath on a continuous basis in the general arrangement of FIG. 1 for the following indicated times and temperatures producing the indicated stress relieved mechanical properties:

FTHERMAL Mechanical lropr-rllvs Bath Diameters Elong. Range Sample Tlmv, Temp, UTS, Ya, Percent No. sec. F, K 5.1 s.l. in 10'' In. In.

. 072 835 14. l 24 21. l 0188 074 832 14. 5 10. 3 21. 3 0188 0186 3 080 835 14. 2 10. 0 21. 4 0186 4. .101 835 14. 4 in, u 20. a .0187 5 I55 835 I3. 7 l ll 23. ii 0191 6 l4. 1 8. H .23. 0 0192 7 l3. 8 8. 7 23. 8 0193 l4.6 11.1 17.2 .0100 14.0 11.0 10.0 .0100 H 14. 7 11. l 17. 7 0101 14. 2 10. 9 20. 7 0103 13. ll 0. 6 21. 6 0193 i 6 in similar manner, 17 B&S gauge EC wire in the H-1 9 o dicated immersion times yielding the following stress relieved dition having an initial ultimate tensile strength of 26.3 k.s.i., meChafliCal p p t an initial yield strength of 24.4 k.s.i., and an elongation of 1.2 inches in inches of length having a diameter range of 0.0453 to 0.0456 was subjected to molten lead bath tempera- 5 TABLE v tures and times as indicated in the following table producing Mechanical properties the indicated stress relieved mechanical properties: Bath 5322? Sample Temp, Time, UTS, YS. percent No. sec. Ks.i. Ks.i. in 10 In. In. TABLE II.MRD LEAD BATH-CONTINUOUS THERMAL 7 070 .155 14.9 9.6 21.9 0425 .0432 TREATMENT 17 Bdls GAUGE EC WIRE 960 14.8 H 2L6 0429 M32 965 .071 15.0 10.2 20.3 0424 .042 Mechanical Properties Bath Diameters 2p E1ong., Range 3%: $5: 3: $532 In In For comparison purposes, EC aluminum wire in the H-l9 condition was placed in an air furnace for 15 minutes dwell 750 .44 15.5 10.9 24.0 .0448 .0450 750 A4 15.6 In 266 0448 0450 time having initial mechanical properties comprislng an ultig8 .82? is? fi-g 39 -$1' mate tensile strength of 26.8 k.s.i.. a yield strength of 24.7 760 I 1 10451 :0457 k.s.i., and 0.96 percent elongation in 10 inches having a 55 2 2% ig-g 3-? gig 332g 822g diameter of 0.0200 inch yielding the following results for the 815 L47 14.4 1014 19:0 10416 0423 indicaledlimesi 815 .176 14.3 10.9 17.4 0445 .0447 815 .099 14.1 10.1 19.8 0445 .0446 815 1&3 0442 g TABLE VI.AIR FI*RNA(E15!\IINITES DWELLEC 25 WIRE Mo aniicah m a propcrtvs 17 B&S gauge EC wire in the H-i9 condition having an im- Diameter tial ultimate tensile strength of 28.3 k.s.i., a yield strength of g UTSI Y5 5. mm 2i 25.5 k.s.i., an elongation of i.l inches in 10 inches of length, N

F. K s.i. s.i. in 10 I11. I11.

and a diameter range of 0.0450 to 0.0454 was continuously 450 18. 5 17.4 treated in the apparatus shown in FIG. 1 for the indicated tem- $38 g-g glgg 0200 peratures and times yielding the following mechanical proper- 5 3:; :1 in: 3 oiuo "1020i ties:

Again, for comparison purposes. EC aluminum wire in the -l9 condition having an initial ultimate tensile strength of 29.3 k.s.i., an initial yield strength of 25.l k.s.i.. and an initial TABLE III.MRD LEAD BATH-CONTINUOUS THERMAL TREATMENT 17 BdzS GAUGE EC WIRE Mechanical Propertm 40 percent elongation of L46 percent in i0 inches oflength hav- Bath E Diameters ing a measured diameter range of 0.0452 to 0.0453 was placed Temp" Time, UTS, 3251; Range in an air furnace for 15 minutes dwell time and yielded the fol- F. sec. K s.i. K s.i. in 10" I11. in. lowing results; 825 .45 14. 4 9. 2 21. 8 0440 0446 322 .091 12.6 11.4 54.2. .8 4? .8220

2 .076 1.8 11.0 6 9 825 .070 15.9 11.9 23.1 .0445 .0448 TABLE lllechanicnl properties Diameter Furnace V Elong., range The temperature of the bath was increased to cycle at 880 50 S amplo temp gTsl, K 1 piiclct l i In l F. in order to treat 17 B&S gauge EC wire in the H-l9 condio g g 1 sin an ul i- 450 22.4 22. 0 1.0 .0451 .0455 tion having initial mechanical properties compri g t 550 16-5 13.6 18.8 0451 0453 mate tensile strength of 28.7 k.s.i., a yield strength of 26.0 700 1&9 (W 25.3 0450 M53 k.s.i., and an elongation of 1.3 percent in 10 inches oflength. a 350 9 3 diameter range of 00452-00456. The wire was treated in a lead bath in an apparatus as shown in FIG. 1 for the indicated times yielding the following stress relieved mechanical proper- The apparatus of FIG. I was set up to test 17 B&S gauge ties: wire subjected to the bath temperature and times indicated and the samples had their conductivity measured by way of a 60 Hoo es Brid e in ercent IACS (international Annealed P B P TABLE IV Copper Standard) with the following results whose values are believed to be accurate to within 1 1% percent: Mechanical properties Bath Diameter M Elong. range Sample Temp., Time, UIS, YS, percent No. F. sec. K s.i. K s.i. in 10" In. In. TABLE VIII 880 .46 14 8 8 0 21.9 .0442 .0445 Bath Conduc- 880 .104 14 6 0 6 23.3 .0434 .0440 tivity. Dimnotvi'rangv 880 .071 14 8 9 8 21.8 .0441 .0474 Temp., 'Iimc, pci'cvnt Sample No. F. sec. lACs in. in 1 965 .071 .0408 2 965 .071 .0427 3 880 .071 .0451; Similarly. additional aluminum wire l7 8&8 gauge in the gig 3K" 822:: 1 EC wire in the H-l9 condition having initial mechanical pro- 6 750 .0 0 .0447 perties similar to those shown for the wire in tables ill and iV g were cycled at the indicated temperatures and for the in- Estimatcd. H

In addition, corrosion tests have been completed on some representative aluminum wire samples. The tests involved exposure for 30 days at 100 percent humidity at 144 F. No harmful residue was found on these samples. Thus no pitting. no corrosion and no staining was observed on samples which were treated as follows:

a. as lead bath processed, unquenched b. as lead bath processed. water washed c. as lead bath processed. then soaked overnight in 4:]

"N then rinsed.

From the foregoing tables it will be observed that recovery rather than recrystallization seems to be effected by the continuous molten metal bath treatments. This is consistent with the microstructures observed of the treated samples.

For purposes of illustration and without limitation, typical bore diameters for the exit stripper elements 64 and 76 were 0.0201 inch for an aluminum wire diameter of 0.0198 inch and 0.0465 inch for a diameter of 0.0456 inch. it was found, for example, that a bore of 0.021 inch functioned better than a bore of 0.0225 inch for a wire diameter of 0.0198 inch.

While it was initially thought that the entrance and exit stripping means had to float on the molten metal bath, it has now been found that fixed as well as floating positions may be used. While the tabulated data contained herein are for speeds up to about 1,000 feet per minute speeds as high as 3,000 feet 7 per minute have now been run satisfactorily and it is believed that speeds up to 5,000 feet per minute will not pose any impossible problems for the present invention. As more rapid speeds are employed, larger feed rollers and wheels are required to maintain friction within satisfactory limits. Graphite coated aluminum wheels and rollers may be employed.

When the molten bath comprises lead and bismuth, a composition of about 50 50 is preferred. When the molten bath comprises lead and tin, 40 percent by volume of lead and 60 percent by volume of tin is preferred. However, in all molten metal baths used in this invention. a wide range in composition is permissible since all bath ingredients have been selected on their nonwetting characteristic for aluminum-containing material.

While presently preferred embodiments of the invention have been illustrated and described, it will be recognized that the invention may be otherwise variously embodied and practiced.

What is claimed is:

1. An apparatus for stress relieving a substantially continuous length of aluminum-containing material which comprises:

a. tank means for containing a molten metal bath,

b. a molten metal bath in said tank means selected from the group consisting of lead. lead and tin, and lead and bismuth,

c. means for feeding said substantially continuous length of said aluminum-containing material into and out of said tank means so as to immerse portions of said aluminumcontaining material for aperiod of time less than about 1 second,

d. and stripper means substantially surrounding the entire exterior surface, of said aluminum-containing material for stripping the molten metal bath material therefrom as said aluminum-containing material emerges from said molten metalbath.

2. An apparatus for stress relieving a substantially continuous length of aluminum-containing material as defined in claim 1 wherein said continuous length of aluminum-containing material is aluminum wire.

3. An apparatus for stress relieving a substantially continuous length of aluminum-containing material as defined in claim 1 including means for heat insulating said stripper means whereby said stripper means is maintained at a temperature at least as great as the melting temperature of said molten metal bath material.

4. An apparatus for stress relieving a substantially continuous length of aluminum-containing material as defined in claim 1 including means to vary the length of travel that said aluminum-containing material is immersed in said molten metal bath.

5. An apparatus for stress relieving a substantially continuous length of aluminum-containing material as defined in claim 1 wherein said stripper means includes first and second longitudinally spaced stripper elements contained by a heat insulating means.

6. An apparatus for stress relieving a substantially continuous length of aluminum-containing material as defined in claim 1 including means to quench said aluminum-containing ous length of aluminum-containing material as defined in claim 2 wherein said means for feeding said aluminum wire into and out of said tank means includes graphitic carbon wheels on graphitic carbon bushings.

9. An apparatus for stress relieving a substantially continuous length of aluminum-containing material as defined in claim 2 wherein said aluminum wire is fed into and out of said molten metal bath as speeds in excess of 500 feet per minute.

10. An apparatus for stress relieving a substantially continuous length of aluminum-containing material as defined in claim 2 including means to vary the length of travel that said aluminum-containing material is immersed in said molten metal bath.

11. An apparatus for stress relieving a substantially continuous length of aluminum-containing material as defined in claim 2 wherein said stripper means includes at least one orifice having a diameter only slightly larger than the diameter of said aluminum wire.

12. An apparatus for stress relieving a substantially continuous length of aluminum-containing material as defined in claim 2 wherein said stripper means includes at least two longitudinally spaced orifices each having a diameter only slightly larger than the diameter of said aluminum wire.

13. An apparatus for stress relieving a substantially continuous length of aluminum-containing material as defined in claim 2 including means to quench said aluminum wire following its emergence from said molten metal bath.

14. An apparatus for stress relieving a substantially continuous length of aluminum-containing material as defined in claim 7 wherein said stripper means includes first and second longitudinally spaced stripper elements contained by said heat insulating means.

15. An apparatus for stress relieving a substantially continuous length of aluminum-containing material as defined in claim 14 wherein said first stripper element is provided with channel means to return molten metal stripped from said aluminum wire into said molten metal bath.

16. An apparatus for stress relieving a substantially continuous length of aluminum-containing material as defined in claim 14 wherein said first stripper element is provided with a longitudinal bore only slightly larger than the diameter of said aluminum wire and is further provided with a plurality of holes extending at right angles to said longitudinal bore thereby providing a series of orifices.

17. A method of making lead particles comprising the steps of a. providing a bath of molten lead,

b. feeding a metal wire into and out of said lead bath,

c. providing a stripping means at the point of emergence of said metal wire from said lead bath,

1. said stripping means having an orifice diameter sufficiently larger than the diameter of said metal wire to permit the formation of lead particles.

18. A method of making lead particles as defined in claim 17 including the additional steps of feeding said metal wire-to a rewinding station and separately collecting said lead particles.

i i i i t 

2. An apparatus for stress relieving a substantially continuous length of aluminum-containing material as defined in claim 1 wherein said continuous length of aluminum-containing material is aluminum wire.
 3. An apparatus for stress relieving a substantially continuous length of aluminum-containing material as defined in claim 1 including means for heat insulating said stripper means whereby said stripper means is maintained at a temperature at least as great as the melting temperature of said molten metal bath material.
 4. An apparatus for stress relieving a substantially continuous length of aluminum-containing material as defined in claim 1 including means to vary the length of travel that said aluminum-containing material is immersed in said molten metal bath.
 5. An apparatus for stress relieving a substantially continuous length of aluminum-containing material as defined in claim 1 wherein said stripper means includes first and second longitudinally spaced stripper elements contained by a heat insulating means.
 6. An apparatus for stress relieving a substantially continuous length of aluminum-containing material as defined in claim 1 including means to quench said aluminum-containing material following its emergence from said molten metal bath.
 7. An apparatus for stress relieving a substantially continuous length of aluminum-containing material as defined in claim 2 including means for heat insulating said stripper means whereby said stripper means is maintained at a temperature at least as great as the melting temperature of said molten metal material.
 8. An apparatus for stress relieving a substantially continuous length of aluminum-containing material as defined in claim 2 wherein said means for feeding said aluminum wire into and out of said tank means includes graphitic carbon wheels on graphitic carbon bushings.
 9. An apparatus for stress relieving a substantially continuous length of aluminum-containing material as defined in claim 2 wherein said aluminum wire is fed into and out of said molten metal bath as speeds in excess of 500 feet per minute.
 10. An apparatus for stress relieving a substantially continuous length of aluminum-containing material as defined in claim 2 including means to vary the length of travel that said aluminum-containing material is immersed in said molten metal bath.
 11. An apparatus for stress relieving a substantially continuous length of aluminum-containing material as defined in claim 2 wherein said stripper means includes at least one orifice having a diameter only slightly larger than the diameter of said aluminum wire.
 12. An apparatus for stress relieving a substantially continuous length of aluminum-containing material as defined in claim 2 wherein said stripper means includes at least two longitudinally spaced orifices each having a diameter only slightly larger than the diameter of said aluminum wire.
 13. An apparatus for stress relieving a substantially continuous length of aluminum-containing material as defined in claim 2 including means to quench said aluminum wire following its emergence from said molten metal bath.
 14. An apparatus for stress relieving a substantially continuous length of aluminum-containing material as defined in claim 7 wherein said stripper means includes first and second longitudinally spaced stripper elements contained by said heat insulating means.
 15. An apparatus for stress relieving a substantially continuous length of aluminum-containing material as defined in claim 14 wherein said first stripper element is provided with channel means to return molten metal stripped from said aluminum wire into said molten metal bath.
 16. An apparatus for stress relieving a substantially continuous length of aluminum-containing material as defined in claim 14 wherein said first stripper element is provided with a longitudinal bore only slightly larger than the diameteR of said aluminum wire and is further provided with a plurality of holes extending at right angles to said longitudinal bore thereby providing a series of orifices.
 17. A method of making lead particles comprising the steps of a. providing a bath of molten lead, b. feeding a metal wire into and out of said lead bath, c. providing a stripping means at the point of emergence of said metal wire from said lead bath,
 18. A method of making lead particles as defined in claim 17 including the additional steps of feeding said metal wire to a rewinding station and separately collecting said lead particles. 